Pre-stress corrosion-resistant tubular pile used in special coastal geological conditions and manufacturing method

ABSTRACT

A pre-stress corrosion-resistant tubular pile used in special coastal geological conditions and manufacturing method thereof is disclosed. The raw materials and proportions of the pre-stress corrosion-resistant tubular pile are as follows: 350-450 parts by weight of cement; 90-135 parts by weight of an ore powder; 600-700 parts by weight of sand; 100-120 parts by weight of stones; water and a water reducing agent; wherein the cement and ore powder are gels; the weight ratio of water to the gels is 0.30-0.31, and the mass ratio of the water reducing agent to the gels is (1.8-2.2):100.

TECHNICAL FIELD

The present invention relates generally to a tubular pile, andspecifically to a pre-stress corrosion-resistant tubular pile used inspecial coastal geological conditions.

BACKGROUND

In a variety of harsh environments, such as in coastal areas, concretessuffer long-term corrosion of salts, causing cracking of the concretes,thereby reducing the durability of the concretes. Among the salts,sulfate and chlorine salt play the major role. How to effectivelyprevent corrosion damage of reinforced concrete in the chloride andsulfate environment, to ensure safe and normal operations duringdesigned service life, and to reduce repair and maintenance costs, hasaccordingly become an important topic of common concern in today'sworld.

Therefore, a tubular pile which can resist strong corrosion is needed.

SUMMARY OF THE INVENTION Objects of the Invention

The purpose of the invention is to develop a tubular pile which canresist strong corrosion, to reduce maintenance costs of the tubularpile.

Technical Solutions

The present invention provides a pre-stress corrosion-resistant tubularpile used in special coastal geological conditions, raw materials andproportions of the pre-stress corrosion-resistant tubular pile are asfollows:

350-450 parts by weight of cement;

90-135 parts by weight of an ore powder;

600-700 parts by weight of sand;

100-120 parts by weight of stones;

water and a water reducing agent;

wherein the cement and ore powder are gels; the weight ratio of water tothe gels is 0.30-0.31, and the mass ratio of the water reducing agent tothe gels is (1.8-2.2):100.

The cement has a grade of 525, a specific surface area of greater than330 m2/kg, 3-day compressive strength of not less than 32 Mpa, and28-day compressive strength of not less than 61 Mpa.

The particle size of the stone is 5˜25 mm, the mud content of the stoneis not more than 1%, and the stone crushing index is less than 8.

Fineness modulus of the sand is 2.6˜3.0, and clay content thereof doesnot exceed 0.9%.

Concrete water reducing rate of the water reducing agent is not lessthan 25%.

7-day activity index of the ore powder is not less than 95, and 28-dayactivity index is not less than 105.

As one embodiment, its raw materials and proportions are:

135 parts by weight of water;

315 parts by weight of cement;

135 parts by weight of an ore powder;

605 parts by weight of sand; and

9.5 parts by weight of a water reducing agent.

The weight ratio of the ore powder to the cement is 3:10.

The present invention further provides a method for producing the abovepre-corrosion tubular pipe, comprising the following steps of:

(1) putting the raw materials into a forced mixer according to theproportions, and mixing them for 2˜3 minutes to make the slump of theconcrete reach 3˜5 cm;

(2) putting the mixed concrete into a mold mounted with a reinforcementcage skeleton by a distributing device, and carrying out pre-stressstretch after completion of the distribution, the tensile force is78%˜82% of the total strength of the pre-stress reinforcement;

(3) sealing the mold after four stages of standing, low speedcentrifugation, mid-speed centrifugation and high speed centrifugationuntil the tubular pile molding;

(4) carrying out steam curing twice, with first entering into theconservation pool with the mold with a curing temperature of 85˜90 andtime of 3.5˜4.5 hours and a stripping strength of not less than 55 Mpa;then carrying out demoulding curing by heating to 175˜185 to makeconstant temperature and constant pressure curing with the pressure of0.9—1 Mpa and curing time of 5.5˜6.5 hours; and

(5) uniformly reducing the temperature to room temperature after 2˜3hours, and pulling out and hoisting the concrete.

During processes of the centrifugation, rotating speed of the low speedcentrifugation is 75˜80 r/min and the time thereof is 2˜3 minutes,rotating speed of the mid-speed centrifugation is 220˜240 r/min and thetime thereof is 1˜2 minutes, and rotating speed of the high speedcentrifugation is 480˜550 r/min and the time thereof is 4˜6 minutes.

Beneficial Effects

The pre-stress corrosion-resistant tubular pile according to the presentinvention can be used in coastal and salt lake areas, having strongcorrosion resistance and long service life, and significantly reducesmaintenance costs.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a lateral schematic diagram according to embodiments of thepresent invention; and

FIG. 2 is a longitudinal schematic diagram according to embodiments ofthe present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

While the present invention is now further illustrated referring toaccompanying drawings and specific embodiments, it should be understoodthat these embodiments are used only to describe the invention but notto limit the scope of the invention, having benefit of this disclosure,those skilled in the art will appreciate that any equivalent form ofmodifications to the present invention is fallen in the scope as definedin appended claims of this application.

In Embodiment 1, raw materials of the tubular pile are preparedaccording to parts by weight as follows: 350 parts of cement; 100 partsof ore powder; 650 parts of sand; 100 parts of stones; wherein thecement and ore powder are gels, the weight ratio of water to the gels is0.30, and the mass ratio of the water reducing agent to the gels is1.8:100.

In Embodiment 2, raw materials of the tubular pile are preparedaccording to parts by weight as follows: 360 parts of cement; 90 partsof ore powder; 700 parts of sand; 105 parts of stones; wherein thecement and ore powder are gels, the weight ratio of water to the gels is0.30, and the mass ratio of the water reducing agent to the gels is1.8:100.

In Embodiment 3, raw materials of the tubular pile are preparedaccording to parts by weight as follows: 380 parts of cement; 110 partsof ore powder; 600 parts of sand; 120 parts of stones; wherein thecement and ore powder are gels, the weight ratio of water to the gels is0.31, and the mass ratio of the water reducing agent to the gels is2.0:100.

In Embodiment 4, raw materials of the tubular pile are preparedaccording to parts by weight as follows: 400 parts of cement; 110 partsof ore powder; 700 parts of sand; 115 parts of stones; wherein thecement and ore powder are gels, the weight ratio of water to the gels is0.30, and the mass ratio of the water reducing agent to the gels is2.0:100.

In Embodiment 5, raw materials of the tubular pile are preparedaccording to parts by weight as follows: 420 parts of cement; 100 partsof ore powder; 600 parts of sand; 114 parts of stones; wherein thecement and ore powder are gels, the weight ratio of water to the gels is0.305, and the mass ratio of the water reducing agent to the gels is2.1:100.

In Embodiment 6, raw materials of the tubular pile are preparedaccording to parts by weight as follows: 450 parts of cement; 90 partsof ore powder; 600 parts of sand; 120 parts of stones; wherein thecement and ore powder are gels, the weight ratio of water to the gels is0.30, and the mass ratio of the water reducing agent to the gels is2.2:100.

In Embodiment 7, raw materials of the tubular pile are preparedaccording to parts by weight as follows: 430 parts of cement; 110 partsof ore powder; 700 parts of sand; 110 parts of stones; wherein thecement and ore powder are gels, the weight ratio of water to the gels is0.31, and the mass ratio of the water reducing agent to the gels is1.9:100.

In Embodiment 8, raw materials of the tubular pile are preparedaccording to parts by weight as follows: 350 parts of cement; 100 partsof ore powder; 650 parts of sand; 100 parts of stones; wherein thecement and ore powder are gels, the weight ratio of water to the gels is0.30, and the mass ratio of the water reducing agent to the gels is1.8:100.

In Embodiment 9, raw materials of the tubular pile are preparedaccording to parts by weight as follows: 100 parts of water; 315 partsof cement; 135 parts of ore powder; 605 parts of sand; and 9.5 parts ofwater reducing agent.

In the above embodiments, the required parameters of the raw materialsare: The cement has a grade of 525, a specific surface area of greaterthan 330 m2/kg, 3-day compressive strength of not less than 32 Mpa, and28-day compressive strength of not less than 61 Mpa. The particle sizeof the stone is 5˜25 mm, the mud content of the stone is not more than1%, and the stone crushing index is less than 8. the fineness modulus ofthe sand is 2.6˜3.0, and the clay content does not exceed 0.9%; theconcrete water reducing rate of the water reducing agent is not lessthan 25%; the seven-day activity index of the ore powder is not lessthan 95, and the 28-day activity index is not less than 105. Eachembodiment includes three parallel groups.

Raw materials of each above group is made into a tubular pile with thefollowing method:

1. putting the raw materials into a forced mixer according to theproportions, and mixing them for 2˜3 minutes to make the slump of theconcrete reach 3˜5 cm;

2. putting the mixed concrete into a mold mounted with a reinforcementcage skeleton by a distributing device, and carrying out pre-stressstretch after completion of the distribution, the tensile force is78%˜82% of the total strength of the pre-stress reinforcement;

3. sealing the mold after four stages of standing, low speedcentrifugation, mid-speed centrifugation and high speed centrifugationuntil the tubular pile molding; during processes of the centrifugation,rotating speed of the low speed centrifugation is 75˜80 r/min and thetime thereof is 2˜3 minutes, rotating speed of the mid-speedcentrifugation is 220˜240 r/min and the time thereof is 1˜2 minutes, androtating speed of the high-speed centrifugation is 480˜550 r/min and thetime thereof is 4˜6 minutes.

4. carrying out steam curing twice, with first entering into theconservation pool with the mold with a curing temperature of 85˜90° C.and time of 3.5˜4.5 hours and a stripping strength of not less than 55Mpa; then carrying out demoulding curing by heating to 175˜185° C. tomake constant temperature and constant pressure curing with the pressureof 0.9˜1 Mpa and curing time of 5.5˜6.5 hours; and

5. uniformly reducing the temperature to room temperature after 2˜3hours, and pulling out and hoisting the concrete.

The tubular piles obtained in the embodiments of the present inventionare tested according to GB/T50082-2009, including chloride diffusioncoefficient detection, sodium sulfate solution for sulfate corrosionresistance testing, and performance testing of resistance to waterpenetration.

The experiment results show that the 28d chloride diffusion coefficientof the tubular piles obtained in the above embodiments is less than3×10-12 m2/S, the level of resistance to sulfate corrosion is higherthan KS120, and the level of resistance to penetration reaches P12.

The inventor has also developed a preservative made of a mixture of30-60 parts of ore powder, 5-15 parts of anhydrite, 25-40 parts offlyash, 1-8 parts of limestone, 5-20 parts of zeolite and 5-10 parts ofcerium sulfate all of a specific surface area of more than 400 m2/kg,and the above parts all refer to parts by weight. The preservative isadded in an amount of 1-15% of the total concrete material. Thispreservative composition having a high specific surface area, highsilicon, high alumina and high activity, and having “micro-powderfilling effect” with appropriate matching with the cement, can improvethe concrete compactness of the concrete to improve the flexural andcompressive strength, and can especially cover a layer of protectivefilm of C—S—H gel on aluminate compounds susceptible to erosion, toachieve the effects of sea water corrosion resistance, chloridepenetration resistance, and freeze protection.

FIG. 1 and FIG. 2 are respectively the lateral and longitudinalschematic diagrams according to of the present invention. The specificstructure of the corrosion-resistant tubular pile according to theinvention is hollow cylindrical square pile. FIG. 1 shows a cylindricalhollow pile of a wall thickness L of 90-130 mm and inner diameter D of300-600 mm, and the number of pre-stress reinforcements 1 evenlydistributed in the pile body is 8-12.

FIG. 2 is the longitudinal schematic diagram of a truncated pile of thepresent invention. As can be seen from the figure, an end plate 3 andshroud ring 4 are fixed to one end of the pile, and spiral hooping 2,which is a cold-drawn carbon steel wire of a diameter of greater than orequal to 5 mm, forms an encrypted area L1 and an unencrypted area L2longitudinally.

1. A pre-stress corrosion-resistant tubular pile used in special coastalgeological conditions, characterized in that, raw materials andproportions of the pre-stress corrosion-resistant tubular pile are asfollows: 350-450 parts by weight of cement; 90-135 parts by weight of anore powder; 600-700 parts by weight of sand; 100-120 parts by weight ofstones; water and a water reducing agent; wherein the cement and orepowder are gels; the weight ratio of water to the gels is 0.30-0.31, andthe mass ratio of the water reducing agent to the gels is (1.8-2.2):100.2. The pre-stress corrosion-resistant tubular pile used in specialcoastal geological conditions according to claim 1, characterized inthat, the cement has a grade of 525, specific surface area of greaterthan 330 m²/kg, 3-day compressive strength of not less than 32 Mpa, and28-day compressive strength of not less than 61 Mpa.
 3. The pre-stresscorrosion-resistant tubular pile used in special coastal geologicalconditions according to claim 1, characterized in that, particle size ofthe stones is 5-25 mm, mud content of the stone is not more than 1%, andthe stone crushing index is less than
 8. 4. The pre-stresscorrosion-resistant tubular pile used in special coastal geologicalconditions according to claim 1, characterized in that, fineness modulusof the sand is 2.6-3.0, and clay content thereof does not exceed 0.9%.5. The pre-stress corrosion-resistant tubular pile used in specialcoastal geological conditions according to claim 1, characterized inthat, concrete water reducing rate of the water reducing agent is notless than 25%.
 6. The pre-stress corrosion-resistant tubular pile usedin special coastal geological conditions according to claim 1,characterized in that, 7-day activity index of the ore powder is notless than 95, and 28-day activity index thereof is not less than
 105. 7.The pre-stress corrosion-resistant tubular pile used in special coastalgeological conditions according to claim 1, characterized in that, rawmaterials and proportions of the pre-stress corrosion-resistant tubularpile are as follows: 135 parts by weight of water; 315 parts by weightof cement; 135 parts by weight of an ore powder; 605 parts by weight ofsand; and 9.5 parts by weight of a water reducing agent.
 8. Thepre-stress corrosion-resistant tubular pile used in special coastalgeological conditions according claim 1, characterized in that, theweight ratio of the ore powder to the cement is 3:10.
 9. A method forproducing the pre-stress corrosion-resistant tubular pile used inspecial coastal geological conditions according to claim 1, comprising:(1) putting raw materials into a forced mixer according to theproportions, and mixing for 2˜3 minutes to make the slump of theconcrete reach 3˜5 cm; (2) putting the mixed concrete into a moldmounted with a reinforcement cage skeleton by a distributing device, andcarrying out pre-stress stretch after completion of the distribution,the tensile force is 78%˜82% of the total strength of the pre-stressreinforcement; (3) sealing the mold after four stages of standing, lowspeed centrifugation, mid-speed centrifugation and high speedcentrifugation until the tubular pile molding; (4) carrying out steamcuring twice, with first entering into a conservation pool with the moldwith a curing temperature of 85˜90° C. and time of 3.5˜4.5 hours and astripping strength of not less than 55 Mpa; then carrying out demouldingcuring by heating to 175˜185° C. to make constant temperature andconstant pressure curing with the pressure of 0.9˜1 Mpa and curing timeof 5.5˜6.5 hours; and (5) uniformly reducing the temperature to roomtemperature after 2˜3 hours, and pulling out and hoisting the concrete.10. The method for producing the pre-stress corrosion-resistant tubularpile used in special coastal geological conditions according to claim 9,characterized in that, during processes of the centrifugation, rotatingspeed of the low speed centrifugation is 75˜80 r/min and the timethereof is 2˜3 minutes, rotating speed of the mid-speed centrifugationis 220˜240 r/min and the time thereof is 1˜2 minutes, and rotating speedof the high speed centrifugation is 480˜550 r/m in and the time thereofis 4˜6 minutes.